Vacuum assisted resin transfer molding method, a pressure applying device and a mold arrangement

Abstract

Provided is a vacuum assisted resin transfer molding method for producing a component, in particular a spar cap, of a rotor blade including a lightning protection system, wherein the vacuum assisted resin transfer molding method includes the steps of: a) placing) an electrically conductive beam fiber material of an electrically conductive beam, an electrically conductive fiber mat and an electrical conductor of the component in a mold arrangement electrically connecting the electrically conductive beam fiber material to the electrical conductor by means of the electrically conductive fiber mat, wherein an electrical connection between the electrical conductor and the electrically conductive fiber mat is generated, c) subjecting the mold arrangement to underpressure, d) applying an external pressure on the electrical connection from outside the mold arrangement, e) injecting resin into the underpressurized mold arrangement, and f) applying heat to the mold arrangement for curing the resin.

The invention claimed is: 
     
       1. A vacuum assisted resin transfer molding method for producing a component of a rotor blade comprising a lightning protection system, the vacuum assisted resin transfer molding method comprising:
 a) placing an electrically conductive beam fiber material of an electrically conductive beam, an electrically conductive fiber mat and an electrical conductor of the component in a mold arrangement; 
 b) electrically connecting the electrically conductive beam fiber material to the electrical conductor by means of the electrically conductive fiber mat, wherein an electrical connection between the electrical conductor and the electrically conductive fiber mat is generated, 
 c) subjecting the mold arrangement to underpressure; 
 d) applying an external pressure on the electrical connection from outside the mold arrangement by inflating an inflatable chamber of a pressure applying device, before resin is injected into the mold arrangement; 
 e) injecting resin into the mold arrangement; and 
 f) applying heat to the mold arrangement for curing the resin. 
 
     
     
       2. The vacuum assisted resin transfer molding method according to  claim 1 , wherein in step d) the external pressure is applied on the electrical connection through a vacuum bag of the mold arrangement. 
     
     
       3. The vacuum assisted resin transfer molding method according to  claim 1 , wherein in step d) the external pressure is applied on a plurality of electrical connections by means of a plurality of pressure applying devices which are arranged in distance from each other along a longitudinal direction of the component. 
     
     
       4. The vacuum assisted resin transfer molding method according to  claim 1 , wherein in step d) the external pressure is applied on the electrical connection by means of filling the pressure applying device with a fluid. 
     
     
       5. The vacuum assisted resin transfer molding method according to  claim 4 , wherein in step d) the fluid inflates the inflatable chamber of the pressure applying device for deforming a flexible film thereof, and wherein the external pressure is applied to the electrical connection by means of the flexible film. 
     
     
       6. The vacuum assisted resin transfer molding method according to  claim 5 , wherein in step d) the flexible film adapts to a geometry of the electrical connection for an even distribution of the external pressure. 
     
     
       7. The vacuum assisted resin transfer molding method according to  claim 5 , wherein in step d) the chamber is inflated with the fluid by means of a manual pump. 
     
     
       8. The vacuum assisted resin transfer molding method according to  claim 1 , wherein the underpressure is reduced before applying heat in step f). 
     
     
       9. The vacuum assisted resin transfer molding method according to  claim 1 , wherein the external pressure provides an extra pressure between 100 mbar and 2000 mbar. 
     
     
       10. The vacuum assisted resin transfer molding method according to  claim 1 , wherein the applying the external pressure occurs during the subjecting the mold arrangement to underpressure.